Hey guys this is my first post and I searched the best I could but could find nothing. So I had my hood popped and with the keys out of the ignition there was a faint buzzing coming from the radiator area. I open'd the overflow coolant side and the buzzing stopped. What the hell right? Closed it and it started again. I topped up the coolant which it took maybe a 1/2 liter total ran it for awhile and it stopped. I've been loosing a little coolant lately but not a whole lot. I have the X model auto. I'm lost, any thoughts would be great!